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Purpose To investigate the value of T2WI mild-moderate signal and restricted diffusion in the context of liver imaging reporting and data system (LI-RADS) (2014 edition) in the diagnosis of hepatocellular carcinoma (HCC) with cirrhosis caused by hepatitis B virus.Materials and Methods A total of 77 lesions (LI-RADS 3-5,size of 1.1 cm×0.7 cm-12.7 cm×9.1 cm) of 69 HCC patients in Beijing Friendship Hospital from January 2012 to November 2016 were retrospectively analyzed.All these patients underwent MRI scan and multiphase dynamic enhanced scan.The images were analyzed by two radiologists.If a disagreement occurred,liver accelerated volume acquisition and multiphase dynamic enhanced scan were combined to reach a consensus.The contrast noise ratio (CNR) and apparent diffusion coefficient (ADC) of T2WI and diffusion weighted imaging (DWI) sequences were compared,as well as the identification of the two signs.Results There was no statistically significant difference between T2WI mild-moderate signal and restricted diffusion in the identification of lesions (LI-RADS 3-5) (P＞0.05),while the sensitivity with DWI b=0 (61.0％) was significantly lower than DWI b=600 s/mm2 (70.1％) (P＜0.05).The CNR of all DWI sequences (b=0,600 s/mm2) were larger than those of T2WI (P＜0.01).The ADC of small lesions (diameter ＜2 cm) were larger than those of larger lesions (diameter ＞2 cm) [(1.57+0.37)×10-3 mm2/s vs.(1.37+0.51)×10 3 mm2/s,P＜0.05].Conclusion There is no significant difference in sensitivity of lesions between T2WI mild-moderate signal and restricted diffusion.However,due to different CNRs,DWI with b=600 s/mm2 is more obvious for the lesions,and can be first investigated in practice.
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Objective To verify the feasibility of a rat model of acute hypertension, and to observe the imaging findings at 7.0T MR scanner of the model.Methods In experimental group, the rats were scanned at 7.0T Bruker MR scanner when phenylephrine was injected continuously to evoke an acute hypertension state.The real time blood pressure was monitored through a femoral arterial catheter connected to a pressure transducer.The control group was infused with saline.T2WI, DWI and T1 mapping were performed in the two rat groups.ADC maps and T1 maps were acquired after image post-processing, and a voxel wise analysis and a ROI analysis were applied.The brain morphology change was evaluated by HE staining.The blood-brain barrier permeability was evaluated by Evans blue staining.Results The T2 images and DWI images of the experiment group showed no abnormal signal intensity changes observed by naked eyes.But ROI analysis of the ADC maps showed that the brain ADC values of the experiment group was higher than the control group (t=3.291,P0.05).The blue dye region was only performed in the experimental group,the results of HE staining corresponded with vasogenic brain edema.Conclusion Continuous infusing of phenylephrine hydrochloride can induce a rat model of acute hypertension.Vasogenic edema and blood-brain barrier permeability change can be observed in the rat model, and the imaging distribution of vasogenic edema can be detected by MRI.